Cotton is a new plant that can be grown in Farming Simulator 19. If you decide to obtain it, it is worth buying a large field (at least 1 ha). The yields are small and the harvester has a very high capacity. Cotton is produced exclusively for sale.
To plant cotton, you only need a treated field and any planter. A special harvester is required for harvesting it: CaseIH Module Express 635. It does not need anything more to work: it collects, stores and processes the resource by itself, without the need for additional headers or semi-trailers during the harvesting phase.
The harvester is quite fast and maintenance-free. It creates huge bales of cotton, which are being released when the tank is full. For a full bale you have to process a 2 ha field, so it is not worth planting cotton on small fields.
You still need the right trailer. Under Tools -> Cotton technology: you will find two models - for one and for two bales of cotton. Once you have started the harvester in the trailer, just drive backwards to the bale lying on the ground to load the bale.